This systematic review evaluates the safety and efficacy of Roux-en-Y gastric bypass (RYGB) on weight loss and anti-reflux outcomes when used as a revisional bariatric surgical procedure after failed anti-reflux surgery. A systematic literature search next to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines was performed for articles published by 30 Mar 2022. After examining 416 papers, 23 studies were included (n = 874 patients). Primary anti-reflux surgery included mainly Nissen fundoplication (16 studies). Reasons for revisional surgery included predominantly gastroesophageal reflux disease (GERD) (reported by 18 studies), obesity (reported by 6 studies), and hiatal hernia (reported by 6 studies). Interval to surgical revision was 5.58 ± 2.46 years (range, 1.5-9.4 yr). Upper endoscopy at revision was performed for all patients; esophageal manometry and pH monitoring were reported in 6 and 4 studies, respectively. Mean body mass index (BMI) at revision was 37.56 ± 5.02 kg/m2 (range, 31.4-44 kg/m2). Mean excess weight loss was 69.74% reported by 12 studies. Delta BMI reported by 7 studies was 10.41 kg/m2. The rate of perioperative complications was 16.7%, including mostly stenosis, leakage, ventral hernia, and small bowel obstruction. Mean improvement rate of GERD was 92.62% with a mean follow-up of 25.64 ± 16.59 months reported in 20 studies. RYGB seems to be an efficient surgical treatment option in failed anti-reflux procedures, but should be performed in experienced centers for selected patients, since the rate of perioperative and long-term complications must be minimized. Cooperation between bariatric and reflux surgeons is essential to offer patients with obesity and GERD the best long-term outcome.